I finally got around to running a somewhat representative test of energy consumption for the aircon in my 2020 Model S (Raven). Note it does not have the heatpump like all newer models do so is significantly less efficient.
Inside set temperature is 21C for all three tests, outside temp 30C for all tests.
Starting drive in the warm car with 30C ambient temp in the garage (no solar heated surfaces, just uniform 30C on all surfaces from the garage temperature) consumes an average of 14 Wh/minute for the aircon compressor on a 58 minute long drive.
Starting drive in the solar heated car (2h in full sun with overtemp protection active at 40C), rolling windows down for half a minute to get rid of the accumulated hot air inside the car, then letting the AC do its thing consumes 41 Wh/minute on a 50 minute drive.
Leaving the aircon running in keep mode while parked in the direct sun with car pre-cooled to 21C inside consumes 11 Wh/minute of energy. Interesting to note that 75% of that energy was used by the heater, not by the aircon (it was exceptionally humid that day, 85% on 30C day).
What does that mean?
You can save net energy in 30C weather and 21C set temperature by keeping the climate running if you are:
- parking the car in the shade if you're leaving the car for 14 minutes or less
- parking the car in the sun, if you're leaving the car for 131 minutes or less (~2 hours).
Inside set temperature is 21C for all three tests, outside temp 30C for all tests.
Starting drive in the warm car with 30C ambient temp in the garage (no solar heated surfaces, just uniform 30C on all surfaces from the garage temperature) consumes an average of 14 Wh/minute for the aircon compressor on a 58 minute long drive.
Starting drive in the solar heated car (2h in full sun with overtemp protection active at 40C), rolling windows down for half a minute to get rid of the accumulated hot air inside the car, then letting the AC do its thing consumes 41 Wh/minute on a 50 minute drive.
Leaving the aircon running in keep mode while parked in the direct sun with car pre-cooled to 21C inside consumes 11 Wh/minute of energy. Interesting to note that 75% of that energy was used by the heater, not by the aircon (it was exceptionally humid that day, 85% on 30C day).
What does that mean?
You can save net energy in 30C weather and 21C set temperature by keeping the climate running if you are:
- parking the car in the shade if you're leaving the car for 14 minutes or less
- parking the car in the sun, if you're leaving the car for 131 minutes or less (~2 hours).
Last edited: